Diabetes is a disease in which the body does not produce or properly use insulin. Approximately 13 million people in the United States have been diagnosed with some form of diabetes. Type 1 diabetes results from the body's failure to produce insulin. Type 2 diabetes results from insulin resistance in which the body fails to properly use insulin. To effectively manage the disease, diabetics must closely monitor and manage their blood glucose levels through exercise, diet and medication. In particular, both Type 1 and Type 2 diabetics rely on insulin delivery to control their diabetes. Traditionally, insulin has been injected with a syringe multiple times during the day, usually self-administered by the diabetic. In recent years, external infusion pump therapy has been increasing, especially for delivering insulin to diabetics using devices worn on a belt, in a pocket, or the like, with the insulin delivered from a reservoir via a catheter with a percutaneous needle or cannula placed in the subcutaneous tissue.
External infusion devices allow Type 1 and Type 2 diabetics to better manage and control their diabetes. The external infusion device is intended to be used continuously and delivers insulin twenty-four hours a day according to a programmed plan unique to each pump wearer. A small amount of insulin, or a basal rate, is given continually. This insulin keeps the user's blood glucose levels in the desired range between meals and overnight. When food is eaten, the user programs the external infusion device to deliver a bolus of insulin matched to the amount of food that will be consumed. The user determines how much insulin will be given based on factors including insulin sensitivity, insulin duration, insulin-on-board, and the like. In many instances, external infusion devices include a processor that assists the user in making therapy decisions based on information provided by the user including blood glucose levels, carbohydrate intake, and/or information from the external infusion device. Exemplary devices are described in U.S. Pat. No. 6,554,798 issued on Apr. 29, 2003 to Mann et al., and entitled “External Infusion Device with Remote Programming, Bolus Estimator and/or Vibration Alarm Capabilities,” which is specifically incorporated by reference herein.
Users of external infusion device therapy rely on the precision and control of the therapy. It is important to minimize unexpected compromises of the infusion device, such as unnoticed cracks that allow liquids to leak into the device. Such leaks could lead to unpredictable device behavior or even failure of the device. Thus, having reliable and robust leak detection is highly desirable so users can engage in activities such as bathing, showering or even walking in the rain without compromising their confidence in the reliability of their external infusion device.